Request to Clarify Equations for Thermal Conductivity
Request to Clarify Equations for Thermal Conductivity
(OP)
Seeking guidance on building a simple rig to measure thermal conductivity for insulating materials, I came across a paper which includes the attached figure and equations. This is a modified version of Lee's disk method.
But when analyzing the equations dimensionally, units did not drop out to just leave W / m / K standing. The paper did not include a derivation for the equations, and I have not been successful yet to find helpful references.
The "a" variables refer to the exposed surfaces of the copper specimens and d refers to the sample thickness. I think all other variables are straightforward.
What am I missing?
But when analyzing the equations dimensionally, units did not drop out to just leave W / m / K standing. The paper did not include a derivation for the equations, and I have not been successful yet to find helpful references.
The "a" variables refer to the exposed surfaces of the copper specimens and d refers to the sample thickness. I think all other variables are straightforward.
What am I missing?





RE: Request to Clarify Equations for Thermal Conductivity
H = e*Aa*Ta + e*Ab*Tb + e*Ac*Tc + e*As*(Ta+Tb)/2 + e*Ah*(Tb+Tc)/2
Where Ts = (Ta+Tb)/2 is the temperature of the specimen
H = VI (power = tension*current)
VI = e*Aa*Ta + e*Ab*Tb + e*Ac*Tc + e*As*(Ta+Tb)/2 + e*Ah*(Tb+Tc)/2
Solve for e
e = VI/[Aa*Ta + Ab*Tb + Ac*Tc + As*(Ta+Tb)/2 + Ah (Tb+Tc)/2]
and not e=VI*[Aa*Ta + Ab*Tb + Ac*Tc + As*(Ta+Tb)/2 + Ah (Tb+Tc)/2]
and then……..
RE: Request to Clarify Equations for Thermal Conductivity
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